#include <iostream>
#include <jsoncpp/json/json.h>
#include <string>

int main()
{
    int a = 10;
    int b = 20;
    char op = '+';

    Json::Value root;
    root["aa"] = a;
    root["bb"] = b;
    root["op"] = op;

    Json::StyledWriter writer;
    Json::FastWriter writer2;

    std::string s = writer.write(root);
    std::string s2 = writer2.write(root);

    std::cout << s << std::endl;
    std::cout << s2 << std::endl;

    return 0;
}
